This time, the $19 billion question is: Who gets to control Oncor Electric Delivery Co.?

Last summer, NextEra Energy of Juno Beach, Fla., outbid other power companies for Oncor, the largest regulated utility in Texas and a major corporate player in downtown Dallas.

Now it’s government’s turn to weigh in.

On Tuesday, the Public Utility Commission in Austin starts hearings to determine if NextEra’s acquisition is in the public interest. A decision probably will come in late April and the process won’t be a rubber stamp.

A year ago, the Ray Hunt family of Dallas and Oncor were in a similar position. While the PUC approved that deal, it imposed conditions that essentially killed it, opening the door for NextEra.

With the Hunts, the key issue was $250 million in annual tax savings from an unusual organizational structure. The PUC wanted the savings to be shared with ratepayers, but the Hunts’ investors wouldn’t agree.

For NextEra, the make-it-or-break-it deal point centers on who calls the shots at the Dallas-based utility.

The PUC staff and others want an independent board to insulate Oncor from NextEra, in case the parent company stumbles. But NextEra said it won’t give up control of an asset that will cost almost $19 billion, including debt. It’s threatened to walk away despite having pursued Oncor for over two years.

In most deals, this wouldn’t be an issue. When one company acquires another, the buyer gets to decide dividend payments, capital spending, operating budgets and the like. In business, the golden rule is often described as those who have the gold, rule.

But the PUC staff and other parties are fixating on the fact that Oncor has operated independently since 2007. That structure helped provide financial stability and growth in revenue and profit even as commodity prices tumbled.

A decade ago, private equity firms bought the former TXU Corp., loaded it up with debt, and renamed it Energy Future Holdings. The PUC had insisted on a so-called ring-fence to separate regulated Oncor from its unregulated units, power generator Luminant and electric retailer TXU Energy.

It was a great call by the commission.

EFH was soon drowning in debt and marching toward bankruptcy, but Oncor and over 3 million customers avoided the damage. Oncor's independent board approved major investments in new transmission lines, smart meters and other infrastructure improvements.

NextEra, which owns Florida Power & Light, is nothing like the financial house of cards that was Energy Future Holdings. It has an A- credit rating, a market value of nearly $59 billion and profit of $2.9 billion last year. On Thursday, Fortune magazine named NextEra the most admired company in the utilities industry for the 10th time in 11 years.

Yet in one measure, there are echoes of EFH, the PUC staff said. Buying Oncor would add billions in debt and NextEra would have much more exposure on the riskier, unregulated side of its business.

Debt on that side would be almost four times higher than on the regulated portion, approaching the old ratio at EFH, the PUC staff wrote in a filing this week.

“NextEra Energy is a financially strong holding company,” the staff report said. “However, the proposed transactions subject Oncor to the same type of risk that proved fatal for EFH.”

NextEra counters that such risks have been considered by independent credit-rating agencies, which have responded favorably. After the deal was announced, Oncor’s debt was upgraded and NextEra’s current rating was affirmed (although S&P Global Ratings would be concerned if NextEra doesn't get full control of the company).

The findings of the credit agencies “invalidate” the many recommendations for more extreme protections, NextEra consultant John Reed said in a filing with the PUC this month.

“That would result in Oncor having the most restrictive ring-fences in utility history,” Reed wrote. That’s not necessary when NextEra’s purchase would “reduce Oncor’s risks and improve Oncor’s credit ratings.”

NextEra agreed to a separate board for Oncor, with NextEra’s CEO appointing eight of 11 members. Half of his appointees would be independent under one definition, but the PUC staff said that doesn't go far enough.

Oncor directors cannot be truly independent if they’re nominated, appointed and subject to removal by NextEra, the report said. The PUC staff wants a majority of directors whose livelihood is not controlled by the parent company.

Otherwise, “NextEra Energy can assume complete authority and control over Oncor’s board and therefore dividends and capital expenditures, a severe and unacceptable departure from the existing ring-fencing,” the staff wrote.

NextEra is trying to satisfy many stakeholders. The PUC has to ensure that the deal is in the public interest. Debtors in the EFH bankruptcy want to maximize recoveries from the Oncor sale. And NextEra investors worry about lower earnings and credit downgrades.

The PUC staff noted that NextEra is paying a $3.7 billion premium for Oncor, in part because the Texas operation would improve the business mix. NextEra also chose to refinance much of the Oncor-related debt instead of paying it off or selling more shares.

Those are NextEra’s calls, of course, but the PUC staff said ratepayers shouldn’t bear the risk of the decisions.

An effective ring-fence is one potential offset. It's a form of insurance, said Geoffrey Gay, who represents cities in utility cases. It may not seem necessary, given NextEra’s current strength, but the PUC has to look ahead.